Congratulations Blade, I am so thrilled for you and excited to follow your name journey. I must admit I was utterly lost when I was looking through your girls thread, but boys names are much more my thing and this list is Fantastic! I think so many of these sound great with Antoine, it's hard to choose a favorite but I narrowed it down to three. I'll also list the ones I like least in hopes of helping you realize your true opinions on them. =]

*Edmund- Strong and handsome, it goes great with Antoine and also most of the mn choices. I love that it starts with a vowel but not another A.Elias- Softer sounds and not quite as nice as Edmund in my personal opinion, but still really a great choice with big brother's name.Gerard- I was really drawn to this when I read your list. I'm not sure it is perfect stylistically but it makes me happy to think about in this scenario.Julian- I almost don't mind the N ending here because this is such a lovely name (but Julius would work really well too if you also liked that one).
*Leander- I sixth or seventh or eighth what others have already said, haha. I adore everything about this name and think it's perfect for you.Lionel- Something about these L names really stands out and sounds great to me. I love that it shares the same vowels as Antoine (minus that first A).Malcolm- Not really here nor there for me personally, but I do think it hits the mark for a name from the right category and fits well with the mn's.
*Marius- This is my absolute favorite paired with Antoine. Pure magic. They sound so spectacular together it give me goosebumps to think of this sibset.Victor- Could potentially seem like a bit much to live up to, but I like the sound of those V names. I prefer Vincent but I think you've said that you don't?

(Not my favorites)Ambrose- I am not a big fan of another name starting with A, and aside from that I think you have many much better options on your list.Blaise- This just does not do it for me. I don't think it works all that well and I also would anticipate spelling/pronunciation mistakes.
Cadfael- Sort of nice, but I think you used the better -ael name for Antoine's middle and do you really want them to match that much?Cassian- I also don't really care for names ending with N because that seems a little too close to big brother's name. Cyprian- If I had to choose a name ending with N this would be the one. It's lovely, I'm just not sure it's for you.Evander- This is a really lovely name, but with Antoine I much much prefer the sound of Leander so unfortunately this guy gets cut.Laurence- I do like this name, but I think I prefer the earlier suggestion of Laurent a bit better. Your feelings on that one?Lucian- Same ending letter issue here. Lucius would work better, although I don't particularly care for going with that version either.Peregrine- This name could either be kind of cute because it shares the ending -ine with Antoine or way too cute to use because of that...Sergius- I think this clashes just a bit too much in the first spot but I do really like it as a middle name if you'd consider moving it.Stavros- I can't really picture this cohesively as a little brother's name, sorry. It's just not my style and I think there are plenty great ones above.